Telegraph system.



' To all whom it may concern:

mnrni) srai ns PA ENT .oFFI-O PAUL M. RAINEY, 01E GLEN RIDGE, NEWJERSEY, ASSIGNOR, .BY ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY,INCORPORATED, A CORPORATION OE NEW YORK TELEGRAPH SYSTEM.

Be it known that I, PAUL M. RAINEY, a

.cit-izenof ,the United States, residing at in the county of Essex andGlen Ridge, State of. New Jersey, have invented certain new and usefulImprovements in Telegraph Systems, of which the following is a. full,

clear, concise, and exact description.

This invention relates to telegraph systems of the type wherein a.plurality of lines terminate at, a central oflice, and its principalobjects are to provide an automatic distribution of incoming calls toidle oper atom, and to prevent operators from interfering with abusyline. Y

I For the accomplishment of these ob ects the invention contemplates anautomatic operator selector associated with each line,

together with means for notifying operators that a given line is busy.An overflow signalis likewise provided whereby notification is giventhat all the operators on a selector have been found in a busycondition.

The above and other objects of the invention will be fully set forth inthe following description and claims, and will be more readilyunderstood by reference to the accompanying drawing in which the systemis shown diagrammatically.

The telegraph line L, extending from a central otfice C, may accommodateone or more branch stations 5, each equipped with the" usual key 6,sounder 7 and condenser 8. In busy districts there may be a large numberof such lines terminating at the central ofiice. Each line is associatedat the central ofiice with selecting mechanism whereby,

' when one of the keys 6 of any station on a.

line is depressed, such line is automatically connected to the firstidle operators position at the central office.

The selectingmechanism comprises among other apparatus to be presentlydescribed, a selector switch 10. This selector switch has an arm 11carrying. a pair ofwipers 12 and 13. These wipers are insulated fromeach other and the arm 11 and are adapted to be carried thereby over aplurality of contacts 14 arranged inpairs. Each pair of contacts ll isconnected to an operato|"s posit-ion set 20, 21, etc, the number ot suchSpecification of Letters Patent.

Application filed December 7, 1914.

' Patented Mai. 7; 1916. Serial No. 875,842.

positions being determined by traflic condiset comprises switches22,keys arm 11 moves in the direction of the arrow, the wipers 12 and 18will be successively connected to different operators position. Eachoper ators positionset maybe, and preferably is, connected through inmultiple as shown, to a number of selector switches 10, so that eachoperator may ans er calls originating over a number of telegraph lines.

There are many well known ways of causing the rotary movement of arm 11,but the mechanism preferred consists of a ratchet wheel and a pair ofratchets (not shown) controlled b'y "an electro -magnetic devicecomposed of a stepping magnet "30 and a holding magnet 31. These magnetsare intermittently energized when the proper circuit connections areestablished by interruptions of current caused by'a constantly actinginterrupter 32. The stepping magnet 30' follows 1 .all of these currentchanges and, upon each energization, causes its ratchet to advance thearm 11 one step in the direction of the arrow. The holding magnet 31 ismore sluggish in its releasing action, and. when once energized, willnot release its ratchet during the intervals of no current produced byinterrupter 32. In this way the arm 11 is not allowed to be retracted byits spring (not shown) during short no current intervals, but isreleased and allowed to return to normal on a longer no currentinterval. This type of selector switch is well known, one specific formbeing disclosed in a patent toJ. L. McQuarrie, No. 826.350, issued July17, 1906.

The initiation of the action of selector switch 10 is controlled by astarter relay 35. Starter relay 3:) is provided with two armatures 36and 37, both joined to a grounded battery 38.. LineL normally passesbyway of a movable contact 40 of a quick acting line extending andinterrlmter cut-off relay 41, through the winding of starter relay 35 tobattery 38. W hen, therefore, the key 6 ofany branclrstation on line Lis closed, a circuit is completed for starter relay 35,

similar to lot and 37. Armature 36, upon being attracted, groundsbattery 38, through magnets and '31, a movable contact 42 of relay 41and interrupter thereby starting the step-bystep rotation of arm 11-.

In order to arrest arm position for a connection to-an-idle operator,

'means areprovided whereby the flow of in-' terrupted current throughmaghet 30 and 131; is .stoppedwhen the moving wipers 12 'and" 1.3engagle the pair of contacts 14 associated-with e first idle operatorsposition. A lead from wiper 12 is connected to armature 45 of relay 41,while wiper' 13 is grounded through the left" hand winding 46 of a.slowacting relay 47, left-hand winding 48 of relay 41, and right-hand"windings 49 and 50yof relays 47 and 41, resepctively'. For purpose, tobe hereinafter described, the sum of'the resistances of windings 46 and.48 is made less than the sum of the resi stances'of windings 49 and 50.-Slow actingrelay 47 is provided with 25 tglo. armatures and 56. Armature55 is c 'nnected to battery 38 and armature "56' is grounded and adaptedto play between a back contact 57 and a front contact 58. Back contact57 is joined to a contact spring .60 and an armature 61 of relay 41,while front contact 58 is connected-to relays 41 and 47 between theirright and left-hand windings. Contact 60 is normally held away fromengagement, with 'a companion contact spring 62 by an insulating lug onarm. 11, but makes engagement therewith upon the first stepof theselector switch. In

order to break the circuit, including interrupter 32, andprovidea-steady ground for 40 i magnets 30 and. 31 during the time of aconnection,.re lay 41 is provided with a grounded "armature 63, whichwhen actuated, separates contact 42 fromthe lead to interrupter 32'.

Any or 'all of the operators provided 1 with sets 20, 21, etc., orotheroperat'ors,

- which may be known as sending operators because their positions arenot connected to selecto; switches, may be providedwith connecting sets70, 71, etc. .Each of these sets consists of a connecting plug 75, key76, sounder 7,8, resistance 79, condenser 80, signal 81 and'groundedbattery 82. In order that operators provided with sets such as- 70' and71 may communicate withthe branch stations on line L, "there is placedbefore each such operator a ack 83, all of the jacks associated with thesame line L being connected in multiple and to the wipers 12 and 13 ofthe selector switch associated with that.

are provided with each jack 83, all 'those signals which are associatedwith a given line L being connected in series with ground 11 in theproper.

\be provided to notify the central office attendants that such aselector switch-is overflowing so that some of the operators associatedtherewith may 'berelieved of a part of theirload; This result isaccomplished "by connecting the last contact of the selector switch 10through a suitable resistance 90, an overflow-.ofrelay 91 and aninterrupter 92, to a grounded battery 93. Energization of relay 91causes the flashing of an overflow signal 94 and, since the insulatingsegments of interrupter 92 are wide, as shown, the current from battery93 through contact 14, wiper-13 and relays 41 and 47 is interrupted longenough to elfect the complete deenergization o:f these relays, causingthe selector making connections as shown at 95, one overflow signal .mayaccommodate 'several selector switches.

i The operation ofthe system is asfollows; When any station on line Ldesires to make a call, key 6 is depressed closing a circuit for battery38 through starter relay Starter relay 35 thereupon pulls up itsarinatures 36 and 37; armature 36 closing a circuit for battery 38,through. magnets 31 and 30, contact 42 and interrupter 32. The arm 11 ofthe selector switch thereupon begins to ro tat-e in the direction of thearrow. The attraction of armature 37 completes a circuit for battery 38through all of the busy signals 85, thereby notifying operators equippedwith sending sets 70, 71, etc., that line L is busy, so that during thedisplay of 47 and 41; Signal 28 becomes active, notifying the operatorthat a telegraphic conversation is desired and relays 41 and 47 attracttheirlarmatures. The'pulling up of armature 45 connects line L tothe idle operators set, through the wiper. 1-2. The attraction ofarmature 63 breaks'the circuit for interrupter 32 through the magnets 30and 31, giving these magnets a steady ground, which stops the movementof arm 11 and holds the arm of the selector switch in this positionuntil the call is completed. The pulling up of armature 61 provides aswitch to return to its normal position. By

new, ground "for starter relay 35 through Y contacts 60 and 62, which aspreviously pointed out, became engaged upon the first step of theselector switch, and, since relay 47 is slower acting than relay 41, theattraction of armature 56 does not break one ground connection for relayuntil this new ground is provided through armature 61. Theattraction ofarmature 56 short circuits the two higher resistance windings 49 and 50of relays 47 and 41, providing a lower resistance ground connection onthe contact 14 associated with the operators set, so that if theselector'switch of any other line upon which a call is initiated stepsupon a contact also connected to this operators set, insuflicientcurrent will flow through the relays thereof which correspond to relays47 and 41 to cause their energization to stop the movement of theselector switch. This arrangement insures that the selector switcheswill not step upon the contacts to an operators set which is alreadybusy, but will pick out the first idle operator. Line L is now connectedthrough to the first idle operators set, such operator being notified ofthis fact, by the lighting of signal 28.

Messages may be exchanged by the manipulation of keys 6 and 23 in theusual manner, and busy signals are displayed for all of thecorresponding jacks 83 associated with line L. WWhen a call iscompleted,the operator depresses her release switch 22, whereupon the circuitthrough the windings 46 and 48 of relays 47 and 41 is opened, causingthese relays to release their armatures. The release of armature 45opens the circuit between line L and the operator. The retraction ofarmature 61 opens the holding circuit previously traced for starterrelay 35, while the return of armature 63 opens the steady groundconnection for magnets 30 and 31, and againconnects these magnets to theinterrupter 32. The interrupter 32, however, cannot cause the operationof magnets 30 and 31 because the denergization of starter relay 35 hasopened the circuit at armature 36. The deenergization of magnets 30 and31 a11ows arm 11 to return to its normal ppsition, which conditionshould be obtained before the armatures of relay 47 are completelyretracted. H1811 the armatures of .relays 47 are retracted, theapparatus is again in a normal position.

In case all of the operators associated with switch 10 are found in abusy condition, upon the initiation of a call upon line L, the arm 11makes a complete circuit of all of the contacts 14, at last arrivingupon the contact connected to the overflow relay 91. This relay willthereupon attract its armature to cause the flashing of overflow signal94 and, the nonconducting segments of interrupter 92 being madesufficiently long to nets 30 and 31, in precisely the same manner as fora disconnection caused by the central oflice operator as previouslydescribed, whereupon, the selector switch will return to itsnormalposition.

When one of the operators provided with a set 70, 71, etc., desires tobe connected with a line L, the plug is inserted in the correspondingjack 83,, whereupon a circuit is completed from battery 82, throughsignal 81, plug 75, jack 83 and windings 46, 48, 49 and 50 to ground.Relays 41 and 47-pullup their armatures, as previously described,connecting the operators set directly through'to line L by means ofarmature 45 and contact 40, and operating all of the busy armature 55.When the telegraphic conversation is completed, the operator withdrawsplug 75 from the jack 83, whereupon-all of the apparatus returns tonormal.

The invention claimed is:

1. In a telegraph system, the combination of a telegraph line extendingto a central office, busy signals and sending. sets associated therewithat the central office, selecting mechanism for said line adapted toautomatically connect said line to one-of a plurality of operatorspositions, a pair of electro-responsive devices, circuit connectionswhereby said devices may be brought into action through said line or asaid set, and means controlled by said devices to affect said busysignals.

2. In a telegraph system, the combination of a plurality of telegraphlines terminating at a central office; busy signals and sending setsassociated therewith at a plurality of operators positions atthe'central oflice; selecting mechanism for each'of'said lines adaptedto automatically connect said line to one of a plurality of operatorspositions and comprising a selector switch having a plurality ofcontacts, and an electromechanical actuator therefor; multiplecircuitkconnections extending between the contacts of different saidswitches whereby a plurality of said lines may be extended .to afsingle,operators position; a pair. of electrore'sponsive devices associatedwith each said mechanism; circuit connections therefor whereby ofiice, aselector switch automatically operaefl'ect the complete deenergizationof magsignals 85 before other operatorsthrough telegraph line extendingto a central tive upon the initiation of a call to connect I said lineto the first idle operators position,

calling jacks and busy signals associated; l.

with saiai line at a plurality of operators my name this 5th day ofDecember, A. I)

ositions, said bus si nals bein ooerated 1914. P .Y 1 q when a'cuai isinitiated, and an o'verload slg- P v A I M. RAINFY. nal ngerated by551161 selector swltch when all 51w OPGHHTOFS"130811710118 assoclatedthere- -Wltnessesz Wfl'h are m a. busy condltmn. E. EDLRR,

"in wiiiness whereof, I hereunto subscribe. K. L. SLAHL.

